The PTL 1 discloses a bulb socket structure that in an indoor lighting system mounted in a vehicle and arranged in a ceiling of the vehicle such as an automobile, for example, a plastic socket main body for fixing a bulb such as a wedge base bulb and a pair of feed terminals (terminal) arranged in the socket main body are provided. A base portion of the bulb is inserted into a fixing hole of the socket main body, and the base portion is sandwiched by the pair of the feed terminals. In the bulb socket structure as described in the PTL 1, as shown in FIG. 8, the pair of the feed terminals 101 has a pair of sandwiching pieces 102 for sandwiching the base portion 111 of the bulb 110. The pair of the sandwiching pieces 102 is elastically deformed by inserting the base portion 111 between the sandwiching pieces 102 in a direction away from each other, and thereby the base portion 111 is sandwiched by a biasing force associated with this deformation. Furthermore, in the fixing hole 103 of the socket 100, a spacer 120 is arranged. By the spacer 120, the base portion 111 of the bulb 110 is guided, and movement of the held bulb 110 is controlled. As a result, the bulb 110 can be steady hold in the socket 100.